J - 179 : Calm Waters - Troubling Sea Floors

The Isola Ferdinandea appeared in 1831 a few Miles northwest of Pantelleria

Growing up in the Swiss mountains, my understanding of the sea was limited. For the longest time I believed tsunamis – as depicted in Japanese paintings – were a myth, or an exaggeration at best. It took the tsunami in the Indian Ocean in July 2006 killing thousands in Sri Lanka, Java and Thailand to make me understand that such rare events were real.

Geology of the Marsili Sea Mount and the Aeolian Islands with Stromboli and Vulcano

I also did not know that mountains could rise from the sea floor. There are no volcanos in Switzerland. For me, mountains were structures which stood for eons and never changed - except for erosion. Italy’s sea floor is different though. Whilst the Alps in Switzerland fold as a result of the African plate slowly moving north, the opposite happens in the Tyrrhenian Sea. There, the African plate is pushed below the European. The water inside the African plate heats up and forms channels through which magma rises and forms volcanoes.

The not subducted floor from the once mighty Tethys

now forms the Italian Apennine - mostly sediments

We are now sailing for the 10^th year along ancient trade routes. Only once, in Santorini, did we see a new volcano rise. The Nea Kameni, Santorini’s new caldera, looks hellish as if it had just emerged from the inner most part of the earth. Just blackish stones. No life.

A small Bay at the Nea Kameni, the new Volcano which forms in Santorini's old Caldera

Never though did we experience a sea quake or a tsunami. The rockiest the waves ever got was during the Meltemi between the Peloponnese and Melos in 2017. Two meters high waves washed over our ship. Wind speed reached storm levels. All hands were on deck. Some behind the steering wheel. Others manning the sails. We got through. During all our other trips, the sea was rather calm – as shown in the prospectus of the agencies leasing sail boats to people like us.

The Waves do not look 2 m high but the Spray gives you a good Idea of the Windspeed

This year, we sail over waters which could be more treacherous though. There are many active and dormant submarine volcanos in the Tyrrhenian Sea. The Marsili is the most prominent. Another active seamount is the Palinuro. Vavilov and Magnaghi are older structures, mostly probably extinguished. All of them are part of Italy’s Arc of Fire that stretches from Sicily to north of Rome. Over the eons, the collision of the continental plates in the Tyrrhenian triggers violent events like the eruption of the Vesuvius in 79 AD. It buried Pompeii and Herculaneum, two towns we want to visit this summer. Also very spectacular was the rise of the Isola Ferdinandea, south of Sicily. When it erupted, a new island rose a few meters above sea level but waves eroded the loose debris within a few years.

Plate Tectonics power the Volcanic Activities in the Tyrrhenian

More recently, the world observed the eruption of a submarine volcano in Iceland when the Surtsey island formed and reached the surface in 1963. The Surtsey volcano still exists and is expected to last at least until 2100 when waves will have completely eroded the island again.

Surtsey Volcano during its Rise from the Sea Floor in Iceland in 1963 - it is still there

Luckily, Italy’s submarine volcanos are closely monitored. A tsunami triggered by an eruption or a landslide would cause considerable damage to Italy’s densely populated coast line. The sophisticated sensors will keep us safe this summer when crossing these waters.

The Gas Output of the Marsili and Palinuro Volcano is constantly monitored by Sensors

Palinuro’s summit is only 63 meters below sea level. It erupted last time 10’000 years ago. Marsili’s last eruption, its peak 500 meters below sea level, happened 5’000 years ago. But we will be able to observe the smoking Etna and Stromboli and smell the sulphonic fumes of Monte Vulcano, all three part of the same ARC of Fire.

Models predict a 20 Meters high Tsunami if the Marsili Vulcano in the Tyrrhenian collapses

Whilst these violent eruptions are dangerous, it is an irony of history that they also propelled human development. Without the volcanos there would not be obsidian glass. It helped our neolithic ancestors to become more sophisticated hunters. I also believe that the demand of obsidian triggered the trade in amber, the “Gold of the North”. Eventually the trading tied the economies of Northern Europe to the Mediterranean. Amber was very precious to the Romans. Emperor Nero ordered tons of the material for his festivities. It possibly would never have made it to Rome had not workmen from Lipari made obsidian blades which were then sold on the shores of the Baltic Sea.

  Obsidian Knives are the sharpest Tool Men ever made